In GA patients who recur after resection, patterns of recurrence vary significantly based on Lauren histologic type.

Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appear to be at increased risk for venous thromboembolism (VTE), especially if they become critically ill with COVID-19. Some centers have reported very high rates of thrombosis despite anticoagulant prophylaxis. The electronic health record (EHR) of a New Orleans–based health system was searched for all patients with polymerase chain reaction–confirmed SARS-CoV-2 infection who were either admitted to hospital or treated and discharged from an emergency department between 1 March 2020 and 1 May 2020. From this cohort, patients with confirmed VTE (either during or after their hospital encounter) were identified by administrative query of the EHR.: Between 1 March 2020 and 1 May 2020, 6153 patients with COVID-19 were identified; 2748 of these patients were admitted, while 3405 received care exclusively through the emergency department. In total, 637 patients required mechanical ventilation and 206 required renal replacement therapy. Within the hospitalized cohort, the overall mortality rate was 24.5% and VTE occurred in 86 patients (3.1%). In the 637 patients who required mechanical ventilation at some point during their hospital stay, 45 developed VTE (7.2%). After a median follow-up of 14.6 days, VTE had been diagnosed in 3 of the 2075 admitted who were discharged alive (0.14%). Among 6153 patients with COVID-19 who were hospitalized or treated in emergency departments, we did not find evidence of unusually high VTE risk. Pending further evidence from prospective, controlled trials, our findings support a traditional approach to primary VTE prevention in patients with COVID-19.

Lauren diffuse-type gastric adenocarcinomas (DGAs) are generally genomically stable. We identified lysine (K)-specific methyltransferase 2C () as a frequently mutated gene and examined its role in DGA progression. We performed whole exome sequencing on tumor samples of 27 patients with DGA who underwent gastrectomy. Lysine (K)-specific methyltransferase 2C () was analyzed in DGA cell lines and in patient tumors. was the most frequently mutated gene (11 of 27 tumors [41%]). KMT2C expression by immunohistochemistry in tumors from 135 patients with DGA undergoing gastrectomy inversely correlated with more advanced tumor stage ( = 0.023) and worse overall survival ( = 0.017). KMT2C shRNA knockdown in non-transformed HFE-145 gastric epithelial cells promoted epithelial-to-mesenchymal transition (EMT) as demonstrated by increased expression of EMT-related proteins N-cadherin and Slug. Migration and invasion in gastric epithelial cells following KMT2C knockdown increased by 47- to 88-fold. In the DGA cell lines MKN-45 and SNU-668, which have lost KMT2C expression, KMT2C re-expression decreased expression of EMT-related proteins, reduced cell migration by 52% to 60%, and reduced cell invasion by 50% to 74%. Flank xenografts derived from KMT2C-expressing DGA organoids, compared with wild-type organoids, grew more slowly and lost their infiltrative leading edge. EMT can lead to the acquisition of cancer stem cell (CSC) phenotypes. KMT2C re-expression in DGA cell lines reduced spheroid formation by 77% to 78% and reversed CSC resistance to chemotherapy via promotion of DNA damage and apoptosis. is frequently mutated in certain populations with DGA. KMT2C loss in DGA promotes EMT and is associated with worse overall survival.

Rac1, a Rho GTPase family member, is dysregulated in a variety of tumor types including gastric adenocarcinoma (GA), but little is known about its role in cancer stem-like cells (CSCs). Therefore, Rac1 activity and inhibition were examined in GA cells and mouse xenograft models for epithelial-to-mesenchymal transition (EMT) and CSC phenotypes. Rac1 activity was significantly higher in spheroid-forming or CD44(+) GA CSCs compared to unselected cells. Rac1 inhibition using Rac1 shRNA or a Rac1 inhibitor (NSC23766) decreased expression of the self-renewal transcription factor, Sox-2, decreased spheroid formation by 78–81%, and prevented tumor initiation in immunodeficient mice. GA CSCs had increased expression of the EMT transcription factor Slug, 4.4–8.3 fold greater migration, and 4.2–12.6 fold greater invasion than unselected cells, and these increases could be blocked completely with Rac1 inhibition. GA spheroid cells were resistant to 5-fluorouracil and cisplatin chemotherapy, and this chemotherapy resistance could be reversed with Rac1 shRNA or NSC23766. The PI3K/Akt pathway may be upstream of Rac1, and JNK may be downstream of Rac1. In the MKN-45 xenograft model, cisplatin inhibited tumor growth by 50%, Rac1 inhibition by 35%, and the combination by 77%. Higher Rac1 activity, in clinical specimens from GA patients who underwent potentially curative surgery, correlated with significantly worse survival (p=0.017). In conclusion, Rac1 promotes the EMT program in GA and the acquisition of a CSC state. Rac1 inhibition in GA cells blocks EMT and CSC phenotypes, and thus may prevent metastasis and augment chemotherapy.

Noninvasive and longitudinal monitoring of tumor oxygenation status using quantitative diffuse reflectance spectroscopy is used to test whether a final treatment outcome could be estimated from early optical signatures in a murine model of head and neck cancer when treated with radiation. Implanted tumors in the flank of 23 nude mice are exposed to 39 Gy of radiation, while 11 animals exposed to sham irradiation serve as controls. Diffuse optical reflectance is measured from the tumors at baseline (prior to irradiation) and then serially until 17 days posttreatment. The fastest and greatest increase in baseline-corrected blood oxygen saturation levels are observed from the animals that show complete tumor regression with no recurrence 90 days postirradiation, relative to both untreated and treated animals with local recurrences. These increases in saturation are observed starting 5 days posttreatment and last up to 17 days posttreatment. This preclinical study demonstrates that diffuse reflectance spectroscopy could provide a practical method far more effective than the growth delay assay to prognosticate treatment outcome in solid tumors and may hold significant translational promise.